Effects of Heat Treatment Applications on Some Fundamental Properties of Wood

Wood, a natural material with versatile industrial applications, faces limitations such as low dimensional stability and decay resistance. Significant progress has been made in wood modification research to minimize these problems. Among wood modification methods, thermal treatment has emerged as an effective method for the environmentally friendly wood industry. Research has shown that heat-treated wood has superior properties compared to natural wood (dimensional stability, wettability, and biological resistance). Heat-treated lumber is a good choice for various applications, especially those exposed to air and moisture changes on the ground. However, heat treatment performed under atmospheric conditions (without the use of an inert gas) causes degradation in the wood’s cell walls and middle lamella. Thus, the wood material becomes more brittle (fragile) than untreated wood. Thermally treated lumber with low strength properties is not suitable for use in load-bearing sections of wooden structures. Additionally, the color of the wood darkens as the temperature and duration of the thermal treatment increase. The suitability of these applications for various uses was discussed by evaluating both the advantages provided by heat treatment processes and the potential losses in mechanical properties. In this review study, scientific studies published primarily between 2000 and 2025 were evaluated to comparatively examine the effects of thermal treatment applied to wood on its physical, chemical, mechanical, and biological properties; common findings and differences reported in various studies were synthesized to provide a general assessment for specific application areas.